Investment Securities (Tables)

6 Months Ended

Jun. 30, 2015

Investments, Debt and Equity Securities [Abstract]

Amortized Cost and Estimated Fair Value of Investment Securities Available for Sale

The amortized cost and estimated fair value of investment securities available for sale at June 30, 2015, December 31, 2014 and June 30, 2014 are presented below:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(Dollars in Thousands)
June 30, 2015:
U. S. government agencies	$	14,956	$	—	$	(210	)	$	14,746
State, county and municipal securities		165,070		3,305		(1,003	)		167,372
Corporate debt securities		12,710		184		(58	)		12,836
Mortgage-backed securities		665,274		4,948		(3,022	)		667,200
Total securities	$	858,010	$	8,437	$	(4,293	)	$	862,154
December 31, 2014:
U. S. government agencies	$	14,953	$	—	$	(275	)	$	14,678
State, county and municipal securities		137,873		3,935		(433	)		141,375
Corporate debt securities		10,812		228		—			11,040
Mortgage-backed securities		369,581		6,534		(1,403	)		374,712
Total securities	$	533,219	$	10,697	$	(2,111	)	$	541,805
June 30, 2014:
U. S. government agencies	$	14,950	$	—	$	(505	)	$	14,445
State, county and municipal securities		143,507		3,136		(863	)		145,780
Corporate debt securities		10,805		284		(131	)		10,958
Mortgage-backed securities		361,194		5,435		(2,182	)		364,447
Total securities	$	530,456	$	8,855	$	(3,681	)	$	535,630

Amortized Cost and Fair Value of Available for Sale Securities by Contractual Maturity

The amortized cost and fair value of available-for-sale securities at June 30, 2015 by contractual maturity are summarized in the table below. Expected maturities for mortgage-backed securities may differ from contractual maturities because in certain cases borrowers can prepay obligations without prepayment penalties. Therefore, these securities are not included in the following maturity summary.

	Amortized Cost		Fair Value
	(Dollars in Thousands)
Due in one year or less	$	7,960	$	7,999
Due from one year to five years		47,037		48,246
Due from five to ten years		66,573		67,686
Due after ten years		71,166		71,023
Mortgage-backed securities		665,274		667,200
	$	858,010	$	862,154

Schedule of Gross Unrealized Losses and Fair Value of Securities

The following table details the gross unrealized losses and fair value of securities aggregated by category and duration of continuous unrealized loss position at June 30, 2015, December 31, 2014 and June 30, 2014.

	Less Than 12 Months					12 Months or More					Total
Description of Securities	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(Dollars in Thousands)
June 30, 2015:
U. S. government agencies	$	9,818	$	(138	)	$	4,928	$	(72	)	$	14,746	$	(210	)
State, county and municipal securities		50,294		(680	)		10,404		(323	)		60,698		(1,003	)
Corporate debt securities		7,149		(58	)		—		—			7,149		(58	)
Mortgage-backed securities		238,174		(2,046	)		30,672		(976	)		268,846		(3,022	)
Total temporarily impaired securities	$	305,435	$	(2,922	)	$	46,004	$	(1,371	)	$	351,439	$	(4,293	)
December 31, 2014:
U. S. government agencies	$	—	$	—		$	14,678	$	(275	)	$	14,678	$	(275	)
State, county and municipal securities		15,038		(70	)		19,665		(363	)		34,703		(433	)
Corporate debt securities		—		—			—		—			—		—
Mortgage-backed securities		36,760		(221	)		46,812		(1,182	)		83,572		(1,403	)
Total temporarily impaired securities	$	51,798	$	(291	)	$	81,155	$	(1,820	)	$	132,953	$	(2,111	)
June 30, 2014:
U. S. government agencies	$	—	$	—		$	14,445	$	(505	)	$	14,445	$	(505	)
State, county and municipal securities		4,088		(35	)		29,203		(828	)		33,291		(863	)
Corporate debt securities		—		—			4,945		(131	)		4,945		(131	)
Mortgage-backed securities		25,107		(65	)		51,039		(2,117	)		76,146		(2,182	)
Total temporarily impaired securities	$	29,195	$	(100	)	$	99,632	$	(3,581	)	$	128,827	$	(3,681	)

Summary of Sales Activities in the Company's Investment Securities Available for Sale

The following table is a summary of sales activities in the Company’s investment securities available for sale for the six months ended June 30, 2015, year ended December 31, 2014 and six months ended June 30, 2014:

	June 30, 2015			December 31, 2014			June 30, 2014
	(Dollars in Thousands)
Gross gains on sales of securities	$	41		$	141		$	8
Gross losses on sales of securities		(19	)		(3	)		(2	)
Net realized gains on sales of securities available for sale	$	22		$	138		$	6
Sales proceeds	$	30,113		$	94,051		$	69,768